The coating on the Yankee dryer is one of the most critical components of the entire tissue making process.  It is required to carry out several very important functions:

Protection of the Yankee surface
Sheet control 
Enhancement and control of tissue quality
Improved softness
Bulk control
Maximize productivity

In the early years of tissue making, the papermaker relied on the natural components of the furnish (hemicellulosics, fines, repulping residuals, etc.) to build a protective Yankee coating.  This type of coating was very difficult to control as fiber source and seasonal changes significantly impacted the Yankee coating. 

Hercules pioneered the development of specialty adhesives and release agents to provide the tissue maker with significantly improved control over the creping process and the ability to produce the softness, bulk and absorbency demanded by the consumer.  Over the years, Hercules has developed a broad portfolio of specialty creping adhesives, release agents and coating modifiers to meet our customers ever changing needs.

These technologies are marketed by Hercules under the tradenames of Crepetrol® Creping Technology, Rezosol® Release Technology and Rezosol® Modifier Technology and are available in North America, Europe, Latin America, and Asia Pacific.

Product Selection

Choosing the correct Yankee coating package for each machine requires years of experience and understanding customers' needs and expectations.  It is critical to match the appropriate coating adhesive and release agent or coating modifier to achieve the desired finished product results.  The purpose of this website is to provide some basic answers to commonly encountered problems.  For more in-depth questions and discussions please contact your local Hercules Representative.

Method of Application

Creping adhesives, release agents and adhesion modifiers are typically applied to the Yankee surface via a sprayboom.  The sprayboom is located after both the creping blade and the cleaning blade, and before the pressure roll, using specific geometries and spray pressures to achieve optimum results.  The combined package of adhesive, release and modifier are applied through the same sprayboom.  The adhesive portion will migrate to the hot Yankee surface producing a robust protective layer.  Release agents bloom to the air surface providing blade lubrication and the proper level of adhesion for the sheet.  Adhesion modifiers will control the adhesion force of the package, enabling superior crepe within a much wider range of moisture operation.

An article that provides more information on Yankee spray application systems is available by clicking here.  The article, which is titled "Model Yankee Creping," was published in the April/May 2003 issue of Tissue World.

Recorded Benefits

The following benefits have been recorded from practical applications of Crepetrol® Creping Technology and Rezosol® Release/Modifier Technology.  Not all benefits are realized for all applications.

Increased tissue quality
Reduced picking and edge breaks
Fewer breaks
Increased paper production
Improved moisture profile
Improved sheet softness
Reduced steam consumption
Less downtime for cleaning